CVE-2025-26598: Xorg: xwayland: out-of-bounds write in createpointerbarrierclient()

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-25 · updated 2026-06-29
Weakness: CWE-787

Description

An out-of-bounds write flaw was found in X.Org and Xwayland. The function GetBarrierDevice() searches for the pointer device based on its device ID and returns the matching value, or supposedly NULL, if no match was found. However, the code will return the last element of the list if no matching device ID is found, which can lead to out-of-bounds memory access.

Affected products

Red Hat Enterprise Linux: 7.0, 8.0, 9.0
Kaspersky TigerVNC: all versions
xorg-x11-server: before 21.1.16 — fixed in 21.1.16
X.Org xwayland: before 24.1.6 — fixed in 24.1.6

How to fix

Upgrade to a fixed version: xorg-x11-server 21.1.16; X.Org xwayland 24.1.6. Check the vendor advisory for mitigations.

References

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